Friday, August 22, 2014
Programmable LED Flashers
Parts:
R1______________10K 1/4W Resistor
R2_______________1M 1/4W Resistor
R3_______________1K 1/4W Resistor (See Notes)
C1_______________4ยต7 25V Electrolytic Capacitor
C2______________10nF 63V Polyester Capacitor
D1___________1N4148 75V 150mA Diode
D2______________LED (Any dimension, shape or color)
IC1____________4060 14 stage ripple counter and oscillator IC
P1_____________SPST Pushbutton
SW1____________SPST Toggle or Slider Switch
B1______________3V to 15V Battery or dc power source (See Notes)
uses only one chip and can be useful if a not very precise number of flashes of the LED is needed before reverting to the steady-on state. In fact, connecting D1 Anode to different output pins of the IC, the steady-on state of the LED will be obtained after 2, 4, 8, 16 flashes and so on.
Connecting D1 Anode as shown, the LED will start flashing at about two times per second after power-on and will revert to the steady state after 8 flashes. P1 resets the schema and C1 automatically resets IC at power-on.
Connecting D1 Anode to pin #13 of IC1 the flashes will be 4; to pin #1 will be 16 etc.
The flashing frequency of the LED can be varied by changing the values of R2 and/or C2.
Notes:
* Circuits were tested at 9V supply, but they might work in the 3 - 15V dc supply range.
* The LED current limiting resistor value was calculated for 9 - 12V supply and should be changed to suit different supply voltages.
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